The present invention relates broadly to power amplifiers, and more particularly to a high power high voltage linear simplifier apparatus.
In the prior art, there exists a need for a high-voltage (1-2 kilo-volts) bi-polar amplifier. Presently, neither bi-polar nor field effect transistor complementary transistors are available in this voltage range. As a result of this predicament, the need for a high power, high voltage linear amplifier exists.
The field effect transistor (FET) is a three-terminal device having source, drain and gate electrodes. The source and drain are biased relative to the gate electrode so that the PN junctions between contiguous zones of the semi-conductor are biased in the reverse direction. The potential of the drain, however, is substantially greater than that of the source. The signals to be amplified are applied between the source and gate electrodes, whereby variations in the potential of the gate electrode control the conductivity of the path for the flow of electrical carriers in the intermediate zone from the source to the drain.
The field-effect transistor has an amplification characteristic that is similar to that of a vacuum pentode. It is a voltage controlled device and its input impedance can be very high. In addition, its signal current is composed of carriers of one polarity only a factor which eliminates many of the noise sources associated with conventional transistors. These characteristics of the field-effect transistor provide a highly desirable device for use in amplifiers that can operate from high impedance sources, such as the piezoelectric transducer of hydrophone, or with other medium-to-high impedance sources where outstanding noise performance is required.